Conventionally, in order to make a phone call from a communication terminal such as a cellular phone, the communication terminal displays telephone book data which contains a plurality of telephone numbers of acquaintances and friends in advance. The user selects a desired destination telephone number from the displayed telephone book data, and operates an outgoing call button to make an outgoing call to the selected telephone number.
In this case, a memory in the communication terminal stores, as number data, each telephone number data contained in the telephone book data. Hence, the outgoing call can be made in accordance with the number data merely by selecting the desired telephone number to make the outgoing call.
However, if a third party comes into possession of such communication terminal which has been lost or stolen, the third party may read out highly confidential stored data, such as personal information, as well as the telephone book data stored in the memory in the terminal.
On the other hand, in a recent server-client system, an SBC (Server Based Computing) system [thin client system] has been introduced (e.g., see Jpn. Pat. Appln. KOKAI Publication Nos. 2004-171063 and 2003-158534). In this system, all applications which are input/output and displayed by each communication terminal (a cellular phone, PC, or the like) start and are executed by a server, and the server also manages all files generated along with these applications.
In such a thin client system, the drawing data of application software executed by the server is transferred to the communication terminal to display this drawing data on the communication terminal (e.g., see PCT (WO) 2004-503862).
Accordingly, in this thin client system, the server stores and manages the telephone book data, transfers the drawing data to the communication terminal, and causes it to display the transferred drawing data as needed. This can prevent unauthorized access and disclosure of the telephone book data even if a third party obtains the communication terminal.
In the thin client system, however, any type of data transferred to and received from the server in response to the operation of the communication terminal is the drawing data generated in accordance with the screen of the terminal. Hence, the communication terminal cannot make an outgoing call by directly using the telephone book data received from the server and displayed on the communication terminal.